In a unanimous ruling, the U.S. Supreme Court paves the way for challenges to the use of lethal injection in death penalty cases. The court also expanded the rights of inmates to challenge convictions in federal court based on DNA evidence.

LINDA WERTHEIMER, host:

The U.S. Supreme Court has opened the door for death row inmates to challenge lethal injection. That's the method used for executing the condemned, in all but one state with the death penalty.

Here's NPR Legal Affairs Correspondent Nina Totenberg reports.

NINA TOTENBERG, reporting:

Thirty years ago, lethal injection was conceived of as a more humane way to execute the condemned. But critics charged that the lethal cocktail is now so out of date, and often is administered by such untrained personnel, that it causes needless suffering.

Yesterday, the Supreme Court did not go so far as to invalidate the current system of lethal injection, leaving that decision for another day. But the justices unanimously allowed challenges to go forward in the lower courts.

Mr. DONALD VERRILLI (Defense Attorney for Clarence Hill): The litigation is bringing to light some very serious deficiencies in the procedures that states use and in the medical validity of their approaches. I assume that as these problems are brought to light around the country, the states will clean up their act.

TOTENBERG: Fordham Law Professor Deborah Denno, an expert on lethal injection, says that while the states have put up a good public fight on this issue, privately, they've conceded they're on shaky ground.

Professor DEBORAH DENNO (Professor of Law, School of Law, Fordham University): I think there's substantial evidence that the states are trying to change their lethal injection procedures. They're not advertising it. They're not, you know, coming out and stating that.

TOTENBERG: While the lethal injection procedures vary from state to state, the problem with all of them is that they're based on a three-drug cocktail. First, a dose of short-term anesthesia is administered that, according to reputable studies, does not always last long enough. Then a paralytic is administered that prevents the condemned person from indicating if he's conscious or feeling pain. And third, the lethal dose is administered, in the form of a drug that's extremely painful if the anesthesia has worn off.

Death penalty opponents note that the lethal drug is so painful, that it was abandoned long ago, by the American Veterinary Association for use in killing animals. And, that the drug is banned for putting down pets in 12 states. Veterinarians today, use high doses of barbiturates, that have the double effect of killing pain and shutting down organs. Again, lawyer Donald Verrilli.

Mr. VERRILLI: That's one of the approaches that's being advocated, for around the country, because it would eliminate the need to use the drugs that inflict the risk of horrible pain.

TOTENBERG: In the past, state officials have rejected the use of barbiturates, but Joshua Marquis, vice president of the National District Attorneys' Association, concedes that states may now have to abandon the three-drug cocktail in favor of a strong dose of barbiturates.

Mr. JOSHUA MARQUIS (Vice President, National District Attorneys' Association): That is one of the options that states can come up with. But, my point is, that whatever it is that they reformulate, it will not satisfy those people that are claiming it's cruel and unusual.

TOTENBERG: Death penalty supporter, Kent Scheidegger, of the Criminal Justice Legal Foundation disagrees, however, with Marquee.

Mr. KENT SCHEIDEGGER (Legal Director, Criminal Justice Legal Foundation): At some point, the issue will be resolved, and we will have a lethal injection protocol that is established as valid. And at that point, the issue will go away.

TOTENBERG: The court's lethal injection decision, was one of two death penalty rulings released by the Supreme Court yesterday, both written by Justice Anthony Kennedy. The second case, unlike the first, was not unanimous. By a 5-3 vote, the court expanded the ability of death row inmates to challenge their convictions in federal court based on new DNA evidence.

The ruling came in the case of Paul Gregory House, convicted 20 years ago for the murder of a neighbor in rural Tennessee. At trial, the prosecution told the jury that the motive for the killing was rape and that the physical evidence, both semen and blood, tied House to the crime.

But yesterday, the Supreme Court ruled that new DNA evidence, developed in the last decades, directly contradicted that trial evidence. The semen on the victim's body belonged, not to House, but to the victim's husband. And the blood evidence, the court said, was in such disarray that no conclusions could be drawn.

All of this, the court suggested strongly, should lead to a new trial. But because there was evidence suggestive of guilt too, the court sent the case back to the lower courts for a further hearing.

Peter Neufeld, co-director of the Innocence project, sees the decision as highly significant.

Mr. PETER NEUFELD (Co-Director, Innocence Project): What the Supreme Court did here is, is they created a roadmap, if you will, for lower courts. This is the very first United States Supreme Court case where a person was convicted and sentenced to death, in which post-conviction DNA testing, although, it didn't prove his actual innocence, raised very serious questions about his guilt.

TOTENBERG: Dissenting from the DNA decision, were Chief Justice John Roberts, along with Justices Scalia and Thomas.

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